Back in the early 90s, when I was still at school and words such as "friend" and "message" were nouns as opposed to verbs, a particular incident occurred. For a month or so, a book had been circling among my classmates in which we wrote anonymous mean things about each other, and the statements that were deemed the funniest – invariably, the meanest – would get (anonymous) stars of approval. One day someone wrote in the book that a classmate whom I'll call Rose had made out with her cousin. More details about this fascinating make-out session were added to the book daily, and reading about Rose and her cousin became the only reason any of us wanted to come to school in the mornings. Eventually the writer of the story, whom I'll call Charlotte, couldn't resist claiming the attention she felt was duly hers and let her involvement be known.

The saga now reached peak hysteria and Rose tearfully went to a teacher. Charlotte was forced to admit that she had made the whole thing up, all because she wanted some stars. (Naturally, the most salacious story a privileged, protected 13-year-old girl could think of was someone making out with their cousin.) All of us stared down at the floor as she confessed, because even though we knew Charlotte had now laid herself open to the most deliciously sharp mockery, hadn't we been, in some vague way, worse? And so it was collectively, if wordlessly, decided that this incident would never be mentioned by any of us again. But I remember vaguely thinking: "Won't it be great to be an adult when people won't lie and be randomly mean to look cool?"

Enter stage left: the internet.

As the proud possessor of a history GCSE, I know the pre-internet past is littered with examples of mendacious, even psychopathic adults. But even putting my history GCSE to its fullest use, I cannot recall an era in which so many adults behaved quite so much like children.

"On the internet nobody knows you're a dog," went the famous New Yorker cartoon – but that was written 20 years ago, the Mesozoic age in internet terms, and not only are hidden canine qualities uncovered frequently on the internet thanks to the general air of febrile hysteria, but the internet brings out the dog in a lot of people. Sometimes they eavesdrop on people and publicly humiliate them in order to amuse folks on the internet and attract stars – I mean followers – as in the increasingly popular "live tweeting" of strangers' arguments, romantic encounters and so on. Sometimes they say outrageous things to garner attention (see: Peaches Geldof last week, Katie Hopkins every day). Sometimes they just make stuff up. Occasionally this leads to mob hysteria followed by an about-turn into pious self-righteousness, as has happened with Gale. All of these things existed in the analogue era, but with the internet they are heightened and even condoned. The Gale saga combines so many of the worst elements of digital life it is like a parody of internet bullshittery written by Jonathan Franzen.

It is one of the weird ironies of the internet that just as it can expand one's knowledge infinitely, it frequently encourages an arrested adolescence. That no news organisation bothered to fact-check Gale's story before reporting it illustrates the sort of immature overexcitement that engulfs some people when dealing with the web. Snarkiness, cruelty and public shaming are online's default modes of discourse and there are now apps for grown ups that would have seemed weird to me when I was 13, such as the increasingly popular Lulu, in which women – grown women – rate their ex-boyfriends, along with photos and hashtags. Sure, it's fun to waste time on the internet, and it's sweet to watch the generation gap closing online, with parents "liking" their children's Instagram posts. But it's also weird to see so many adults acting like hormonal and hyperactive 13-year-olds, humiliating others and themselves for the sake of phoney popularity and dubious celebrity. As for those of us who pretty much entered adulthood just as the internet was emerging, we can still only dream about what it must feel like to live in the grownup world.